Nowe a boy raised by a dragon joins the Knights of the Seal, whose purpose is to protect the keys holding the red dragon's seal in place, which prevents the end of the world. Nowe begins to question the ethics of the Knights when he discovers that the keys are powered by the life force of some of the land's citizens. His faith is further shaken when the general, General Gismor, tries to poison him, then reveals that he poisoned his predecessor, General Oror, Nowe's adoptive father.
Source: Wikipedia, "Drakengard 2", available under the CC-BY-SA License.